This is a Barolac pattern (Inwald, Czechoslovakia). I have seen these boxes with the moulded mark and also own a small opalescent pin tray with a variant of the design. I don't know the date of introduction, 1930's or early post war - neither I, nor as far as I know, Siegmar Geiselberger have been able to find a catalogue reference for this pattern. Perhaps Marcus will be able to add more.

As for the Blueprints - we have every intention of showing them all just as soon as we possibly can - and also all our Barolac information. We are just waiting for (hopefully) a little more information to fill in the whole picture. They are amazing, and very lovely.